Optical heart rate sensors work by using light to measure blood flow in capillaries beneath the skin

Enhanced grip on slippery surfaces

Large arm openings to prevent chafing

All seams are taped

so it feels like you're wearing nothing

Brooks Men's Adrenaline GTS 25 2E Width Black/White Bag Optical heart rate sensors work1104542E090 Don't miss the smooth and supportive men's Adrenaline GTS 25, now featuring added cushion in the heel and forefoot for long lasting comfort. Features Soft and dynamic cushioning GuideRails support Secure fit Breathable upper Specs Designed for: Road Midsole drop: 10mm Weight: 10. 6oz 300. 5g Feel under foot: Balanced A blend of soft and dynamic cushioning that offers a smooth feeling with each step. Support: Support EXTRA, EXTRA! Soft and